1. Field of the Invention
The present invention relates to concrete construction utilizing foam block forms, more specifically to improvements to the foam sidewalls used to create a longitudinally bi-directional system, improved form sidewall spacing ties which create enhanced concrete flow, enhanced strength, and enhanced fire-break properties, and a corner form that can be used as a right-hand or left-hand form.
2. Description of the Related Art
Concrete forms made of a polymeric foam material are known. Such forms basically comprise a pair of laterally spaced-apart sidewalls presenting a cavity therebetween. A number of these forms are connected to present longitudinally and vertically aligned cavities for pouring concrete therein.
One such form is shown in U.S. Pat. No. 3,788,020, issued on Jan. 29, 1974. This patent discloses a concrete form with a pair of sidewalls, end walls and intermediate partition walls. A plurality of these forms are connected to present vertical cavities for pouring concrete therein to form a plurality of vertical concrete columns or piers. These vertical columns are connected by a horizontal concrete beam formed by filling a channel with concrete, the channel presented upon placing one row of concrete forms atop another.
One problem with existing concrete forms is that the sidewalls must be immobilized so as to resist pressures on the walls during transport and, more importantly, during concrete pouring and curing. If not, the form sidewalls may shift in lateral and/or vertical and/or longitudinal directions. Such displacements make it difficult to easily connect the forms. Also, the forms may separate along the joints respectively presented along the zones of connection between longitudinally and vertically adjacent forms. If the forms are not sufficiently braced, the concrete can cause these joints to separate. The industry refers to such separations as “blow outs”.
During the pouring of the concrete, a hydraulic concrete load acts on the sidewalls of each form as well as on any structure spanning such sidewalls. The load urges the sidewalls from their proper vertical, lateral and longitudinal spatial relationships. Also, during form transport to the job site, the sidewalls may be displaced due to the weight of other forms stacked thereon. In some cases the distance between the sidewalls may vary. Accordingly, problems will arise when attempting to longitudinally and vertically connect forms as the mating lap joint surfaces and/or tongue/groove elements will not be properly aligned.
The closest related publications known to the inventor are U.S. Pat. No. 4,223,501 granted to DeLozier Sep. 23, 1980 and Published U.S. Application 2004/0045237 invented by Coombs et al and published Mar. 11, 2004. Each of these publications shows concrete forms made of opposing panels. The panels are held in spaced relationship by ties. In the patent publication, the tie contains inadequate open space to allow for the free flow of concrete necessary during a pouring operation in order to avoid air pockets which will weaken the resulting wall. In both of these publications, the tie is a single piece bent at each side to form an anchor. This allows for lateral movement during shipping and a corresponding loss of alignment. When this happens the units do not fit together properly on the construction site.
Also, in both of these publications, the tie is made of metal, which conducts heat and can be a mode of transmitting heat during fire. Additionally, in both of these publications there is no predetermined space for connecting the form to studs.
As seen from the above, various devices in the forms of braces and permanent tension members have been proposed so as to maintain the sidewalls in place to preclude such shifting and/or “blow outs” during concrete pouring and subsequent curing. However, such devices have been relatively complex in construction requiring the sidewalls to have special configurations so as to receive the braces and/or ties and have lacked desirable features.
In prior art systems, corners present some problems. Typically a wall form is extended to the end of the wall and a piece of foam plastic is secured over the end of the wall form by wire or the like.
This type of end is difficult to secure to the wall form, frequently breaks during concrete pouring, and is not securely fastened to the wall form. This creates unnecessary labor in fixing breaks, setting up the forms, and affixing exterior sheathing to the corner of the wall.
In another prior art approach, the specific corner form is provided, but it is preformed for a certain specific job and must be either a right-hand corner or a left-hand corner. Right-hand or left-hand orientation is always determined from a top plan view because these forms have by necessity a top end and a bottom end. Therefore, a right-hand corner form cannot be substituted for a left-hand corner and visa versa. This doubles the number of types of molds required to produce the corner forms, doubles the types of corner forms needed in inventory, increases delivery costs, and so forth.
Therefore, there is a need for a corner form for a concrete wall that is universal, that is, can be used for either a right-hand or left-hand wall corner; that can be securely and easily attached to the wall form; that does not break during concrete pouring; and that is securely fastened to the wall form.